Abstract: An aerobic digestor for rapidly and efficiently composting waste vegetation and the like has a rotatable drum mounted on a horizontal transverse axis at the midpoint of the length on a frame spacing it above the ground a distance sufficient for rotation; a fixed end of the drum mounts a perforate tube coaxially in the drum between the ends and holes in the fixed end and the removable end of the drum admit air for composting to the perforate tube through adjustable shutters; material being composted in the drum receives air through the tube perforations and may be end-for-ended periodically with the drum at which time the shutter on the end being lowered may be closed to force air up through the dropping charge of waste material.

Abstract: A bump-actuable filament feed for vegetation trimmers; when the cutting length of filament breaks or wears short, the user without interrupting cutting simply bumps the cutting head on the ground deploying a fresh cutting-length of filament. Bumping causes a spring-restored spool latch to yield an increment of spool rotation, feeding a corresponding increment of filament from the spool. For replenishing the filament supply when exhausted, the spool snaps out in one embodiment on pressing a button, and a fresh spool as easily snaps into place.For applications in which bumping the cutting head against the ground is not desired an analogous operation is provided by adaptation of the basic structure.

Abstract: A system for producing decorative plates for photoprinting includes forming variously colored translucent wax layers into a laminar bar from which transverse thin sections are cut and mosaicked edge-to-edge on a transparent support, back-lighted and photographed to produce a positive transparency; both pre-sectioning and post sectioning distortions are employed and a matching "open face" disposition pattern provides symmetry.

Abstract: An anti-tangle, feed correcting improvement for line handling in a filament trimmer circular cutting head of manual-feed, commercially available type having a slotted-rim-cup-shape and holding the spool or spools of filament with cutting length of filament emerging from the slot, includes an elongate retainer fixed integrally in the cutting head across the slot at an intermediate location providing room for filament cutting-end swing above the pin and room above and below and behind the elongate retainer for manipulation to feed a fresh length of filament when necessary; in an embodiment provision is made for manually slipping the filament past an end of the elongate retainer to facilitate feeding more filament.

Abstract: A portable map-display system for auto, boat and airplane uses and the like includes a plurality of translucent maps and a compact light box proportioned for back-lighting one map at a time. To prevent unshielded glare from the light-box and to assure proper orientation of maps on the light-box a series circuit arrangement turns off the light circuit in the box when a map is not properly in place over the light-box. The series circuit arrangement includes a conductive strip asymmetrically disposed on each map and a pair of electrodes on the light-box adapted for resiliently receiving the conductive strip of a map between them to close the circuit and turn on the light.

Abstract: Folding planar structure for use as a changing surface for infants, particularly while away from home. A plural-part rigid board assembly includes a unitary cushioning pad cemented to the parts and hinging them together, and has sliding rod structure for board-to-board connection holding the three parts rigidly in plane when in use; parts of the sliding rod structure are always in view and evidence by position whether the assembly is safely secured together. When folded for storage the sliding rod assembly provides handle structure for carrying and also stand structure preventing the assembly from getting wet or soiled when rested on a floor or leaned against a wall.